TORONTO -- So much of Saturday evening's MLS Cup rematch between the Seattle Sounders and Toronto FC inspired déjà vu.

The prematch buildup at BMO Field was just as raucous, if not even more so, than it was last December. The a cappella version of O, Canada from the home crowd brought familiar goosebumps to the fore.

Just as in the 2016 final, TFC controlled the game but struggled to turn that dominance into an actual breakthrough. For an hour, the reigning title-game MVP, Seattle goalkeeper Stefan Frei, was on track for a repeat award following a series of increasingly outlandish saves, and the energy inside the building was infused with a "here we go again" sense of dread.

Then Jozy Altidore split the Sounders' defense up the seam with a well-timed run to finish past a helpless Frei, and everything changed.

The feeling within the away locker room of BMO could not have been more disparate than it was at this time last year. No protective covering in front of the lockers was necessary. Clumps of athletic tape and sod littered the floor, rather than discarded celebratory beer cans. Instead of a heaving, champagne-spraying, dancing mass, the players kept mostly to themselves in their respective stalls, shoulders slumped and eyes watery.

"You feel like you let down a whole city," third-year midfielder Cristian Roldan said. "You feel like you let down yourself, your teammates, your family. It's very tough, emotional. But at the end of the day, you can't do anything about it now. You have to look forward."

Clint Dempsey and the Seattle Sounders fell short of back-to-back MLS Cups, losing 2-0 on Saturday in Toronto.

The vibe was very much reminiscent of a different defeated Seattle finalist from a few years back: the 2014 Seahawks. That group was even more shaken, given the traumatic way they lost, with quarterback Russell Wilson throwing an interception on the New England Patriots' goal line with less than a minute remaining.

Yet there was the same sense of a precious, fleeting opportunity missed. These Sounders, like those Seahawks, would have been back-to-back champions. No matter how strongly you feel about your current team or how unbroken its upward trajectory, those chances don't come around all that often.

No one is more painfully aware of just how much hard work and good luck go into reaching a championship game, let alone winning one, than the athletes themselves.

Seattle forward Will Bruin qualified for MLS Cup in each of his first two seasons as a pro while with Houston. The Dynamo lost both of those finals to the LA Galaxy, the last MLS team to win consecutive titles, but to a youngster such as Bruin, the team's eventual triumph felt like only a matter of time.

It would be five years and would require a change of scenery for Bruin to earn another shot. He spoke earlier this week about no longer taking these moments for granted, and that realization made Saturday's defeat that much tougher to swallow.

"It sucks," Bruin said. "It probably hurts more now because this is such a good team we have. ... It's not every year you get to go to MLS Cup. Hopefully we can keep this group together. If we keep the core of this team, we can learn from this experience. It sucks now, but if we bring back the nucleus and the core, it will make us stronger."

The Sounders have plenty of reasons to believe that they have the pieces in place to make another deep push sooner rather than later. Uruguayan playmaker Nicolas Lodeiro has a contract that runs into the 2019 season, and veteran forward Clint Dempsey recently reupped for another year. Roldan, though he struggled in this final, has become one of the best young players in the league. Jordan Morris, if he can stay healthy, will be a part of the foreseeable future as well.

The defense that hadn't allowed a goal since Oct. 1 prior to Saturday night is a solid foundation to build upon. Seattle mostly waltzed through the West, and the rest of the conference contenders have more glaring question marks.

Still, don't expect the club to sit pat. Within hours of last year's championship, the Sounders declined the contracts of a host of influential veterans, and general manager Garth Lagerwey impressively remade the roster in order to make another run. Expect Lagerwey to keep tinkering in obsessive pursuit of getting back to exactly where his team stood earlier Saturday evening, 90 minutes from another title.

That's the thing about losing a championship game: You never really get the chance to make amends. Even if Seattle wins the next two MLS Cups, the next three, the next five, 2017 will forever be the one that got away, the missing piece of a would-be dynasty.

There are no guarantees. The Seahawks, for each of those winning seasons since, haven't made it back to another Super Bowl. Late Saturday night, in the bowels of a stadium in which they once triumphantly celebrated, the Sounders weren't quite ready to ponder a similar fate.

"Right now, it still feels like a failure," Bruin said. "In a few days, sure, we'll sit back and appreciate what we did. But with the Sounders, sometimes we take things for granted because we hold ourselves to such a high standard that we expect to get where we want to go. That's winning MLS Cup, and we fell short, so right now, it feels like a failure."

Matt Pentz is a Seattle-based soccer reporter covering primarily the Sounders, Timbers and Whitecaps. Follow him on Twitter @mattpentz.